You can adjust and expand the options as you like. A good overview is the wp-admin/options.php.

<?php
/*
Plugin Name: Toscho's basic settings
Plugin URI: http://toscho.de/2010/wordpress-grundeinstellungen-per-plugin-setzen/
Description: Some useful default configuration settings. See 'wp-admin/options.php' for more options.
Version: 0.2
Author: Thomas Scholz
Author URI: http://toscho.de
*/

function set_toscho_defaults()
{
    $o = array(
        'avatar_default'            => 'blank',
        'avatar_rating'             => 'G',
        'category_base'             => '/thema',
        'comment_max_links'         => 0,
        'comments_per_page'         => 0,
        'date_format'               => 'd.m.Y',
        'default_ping_status'       => 'closed',
        'default_post_edit_rows'    => 30,
        'links_updated_date_format' => 'j. F Y, H:i',
        'permalink_structure'       => '/%year%/%postname%/',
        'rss_language'              => 'de',
        'timezone_string'           => 'Etc/GMT-1',
        'use_smilies'               => 0,
    );

    foreach ( $o as $k => $v )
    {
        update_option($k, $v);
    }

    // Delete dummy post and comment.
    wp_delete_post(1, TRUE);
    wp_delete_comment(1);

    return;
}
register_activation_hook(__FILE__, 'set_toscho_defaults');
?>

Here you can download the Plugin by toscho.

Nonetheless, certainly worth a look and now and then a help to quickly look into the settings of the blog. Alternatively, the plugin WP Developer Assistant can help here, because it also allows a glimpse into the serialized data.

Example-URL: http://example.com/wp-admin/options.php

Alternatively you can also add a menu link. Add the following snippet in to the functions.php of your theme or create a Plugin.

function all_settings_page() {
	add_options_page( __( 'All Settings' ), __( 'All Settings' ), 'administrator', 'options.php' );
}
add_action( 'admin_menu', 'all_settings_page' );

echo get_option('blogname');

This snippet is the blog name. In order to use its own options, they must be created first:

add_option('myOptions', 'a Test');

This call writes a new entry myOptions with the value "a Test" in the database. If you have more data to store, you do not have to write every option in a new row of the database table. Taking the data in an array provides a lot faster access.

$myOptions = array(
	'firstOption' => 1,
	'secondOption' => 'second'
);
add_option('myOptions', $myOptions);

In the database it looks like this:

a:2:{s:11:"firstOption";i:1;s:12:"secondOption";s:6:"second";}

Here you can see the data type very nicely. a: is for array, s: for a string and i: for an integer.
To overwrite the options, you use update_option().

$myNewOptions = array(
	'firstOption' => 2,
	'secondOption' => 'my second Option'
);
update_option('myOptions', $myNewOptions);

Now you can work with the stored options.

$myOptions = get_option('MyOptions');
foreach($myOptions as $option => $value) {
	echo $option . " => " . $value . "<br />";
}
/* Output:
firstOption => 2
secondOption => my second Option
*/

echo $myOptions['firstOption'];
/* Output:
2
*/

Options of a plugin or theme should be also deleted if you uninstall them. You delete the options with delete_option.

delete_option('myOptions');

You also can display something depending on the options, if option is 0, do this, if it's 1 do this.

In my theme, which I'm working on right now, I have over 130 options now. It's not very easy to program, if you must access nested arrays.

$myOptions = get_option('MyOptions');
echo $myOptions['first']['foo']['bar']['name];

A really cool alternative is to write the options as an object in the database:

$myOptions = new stdClass();
$myOptions->name = "myOption";
$myOptions->params->param1 = 1;
$myOptions->params->param2 = 'second parameter';
update_option('myOptions', $myOptions);

In our database is now our serialized Object:

O:8:"stdClass":2:{s:4:"name";s:8:"myOption";s:6:"params";O:8:"stdClass":2:{s:6:"param1";i:1;s:6:"param2";s:16:"second parameter";}}

After you grab the options from your database, they are available as object.

$myOptions = get_option('MyOptions');
echo $myOptions->name;
/* Output:
myOption
*/

echo $myOptions->params->param2;
/* Output:
second parameter
*/

What do you do now with the acquired knowledge? I do not know, use your creativity and leave your ideas in the comment section!